Mindset is huge and you will see post about it often.
What we think about ourselves and situation tends to happen, it is like the world gravitates toward what we are thinking (within reason).
If we think negatively, we will naturally react to a situation that comes up aggressively, or in a manner that probably isn't the best.
If we keep a positive mindset, we will treat and react to others and situations much better, giving ourselves a better outcome.
Mindset. It matters.